If she really made the jump, it was all presented technically accurately here. (Speaking as someone who jumped for about 10 years in the 90’s.) I’m betting that she did go through with it.
No, very few non-military people jump from 15K. You’d need supplementary oxygen. Skydivers and tandem pairs typically jump from 9500-10K ft, solo 1st-time students from 3000’.
*Cue